Hyperbaric chambers known in the art are commonly designed for the recompression of divers to mitigate gas embolism, the treatment of patients in a hospital or clinic environment and for diver or athlete training. In much of the art known to the applicant, hyperbaric chambers are massive and complex devices that require expert attendant staff. Such chambers are therefore not suited for home use by individuals without attendants. Moreover, since expert staff will be in attendance while the hyperbaric chambers of the art are in use, no provision is made for the user or patient to open the chamber from within so that he or she can exit without assistance.
In many hyperbaric chambers for use in the clinical environment the patient is required to lie prone in a tube. Indeed, it is important in recompression chambers for the patient to be prone and inclined head-down at an angle of about 30 degrees. This results in the massive construction typical of many such chambers. [See, for example, U.S. Pat. Nos. 4, 727,870 to Krasel, 5,433,334 to Reneau and 6,354,457 to Aaron, and U.S. design Pat. Nos. 346,864 to Reneau and 415,278 to Bowman.] However, it is also important that recompression chambers be capable of being transported to a diver with the bends and rapidly deployed on site. Relatively compact chambers suitable for transport by truck or plane are therefore known in the art. [See, for example, U.S. Pat. Nos. 4,811,729 to Sands et al, 5,378,093 to Santi and 6,321,746 to Schneider. For relatively modest recompression pressures, portable inflatable chambers with flexible walls are also known in the art. [See, for example, the above U.S. patents to Santi and Schneider as well as U.S. Pat. Nos. 5,109,837 and 5,398,678 and to Gamow, 5,255,673 to Cardwell and 5,360,001 to Brill.]
The traditional design of a hyperbaric chamber for use in hospitals and clinics is a cylinder with a round door at one end through which the patient can be introduced in the prone position. Such a design appears to have been dictated by the need to minimize the area of the end door so that the force on the door is modest even when the chamber is fully pressurized. Nevertheless, many such chambers have the appearance and claustrophobic feel of totally enveloping ‘iron lungs’ that prevent the patient from moving significantly—let alone sitting up—and that allow visual contact with the operators through small portholes only. [See, for example, U.S. patent to Krasel above.] The fact that there is generally no way that the user can open the chamber from within exacerbates the natural claustrophobic anxiety associated with enclosure in such a confined space.
Nevertheless, the prior art does disclose designs for hyperbaric chambers that permit the patient to be seated. U.S. Pat. No. 5,327,904 to Hannum and U.S. Pat. No. 6,352,078 to Harvey disclose short cylindrical chambers of sufficient diameter to accommodate a seated person. In the former case a flat door is fitted into the cylindrical shell and in the latter case the door is set into one end. In both cases, however, the doors open inwards (to enhance strength and facilitate sealing under pressure). Since the open door must allow the user entry and, after entry, must clear the seated user as it is being closed, the size of the chamber still needs to be substantial. Hannum nevertheless notes that an important feature of his chamber is that can be made sufficiently compact to fit through double (hospital) doors. Again, both chambers require the attendance of a skilled operator throughout the treatment of the patient or user, including the opening of the door to permit entry and egress at the start and end of the procedure. Thus neither chamber is suited to home use, for installation in a normal house or for use by a person without assistance.
Finally, it is to be noted that U.S. Pat. No. 4,509,513 to Lasley discloses a ‘hyperbaric chamber’ that appears to be suitable for home use by a person without assistance. However, the device is a bag into which the user climbs like a pair of angler's waders, securing the opening around the upper part of the body (below the shoulders and not including the arms) to form a seal. The bag is then inflated with oxygen-enriched air. Obviously this device is not, in fact, a hyperbaric chamber in the normal sense—that is, one intended for pulmonary oxygenation.